Nutrient
composition and metamorphosis success of Atlantic halibut (Hippoglossus
hippoglossus, L.) larvae fed natural zooplankton or Artemia
K. Hamre, I. Opstad, M. Espe, J. Solbakken, G.-I. Hemre, K. Pittman-2002
Aquaculture
Nutrition, 8(2): 139-148
Abstract:
Atlantic halibut larvae were fed
docosohexanoic acid- (DHA) selco enriched Artemia (RH-cysts) or wild
zooplankton in duplicate tanks from first-feeding and 60 days onward.
The zooplankton were collected from a fertilized sea water pond and
consisted mainly of different stages of Eurytemora affinis and Centropages
hamatus. There were no differences in survival, or in growth during the
first 45 days of feeding, between larvae fed the two prey items, but
the larvae fed Artemia showed much higher incidence of
malpigmentation and impaired eye migration than larvae fed zooplankton. The
prey organisms contained similar amounts of dry matter and protein, but Artemia
was higher in lipid and glycogen than the zooplankton. Larvae fed Artemia
were higher in both glycogen and lipid than the zooplankton-fed larvae
towards the end of the feeding period. There were large differences between
the prey organisms in the concentrations of essential fatty acids (% of
total fatty acids) which was reflected in the fatty acid composition of the
larval body. It is concluded that the macronutrient composition of Artemia
in the present study was probably within the optimal range for promotion of
growth and survival in young Atlantic halibut. The concentration of n-3
HUFA, and especially DHA, is however, very much lower in enriched Artemia
than in copepods, and may be one of the factors triggering developmental
errors in Atlantic halibut.
(Institute of Nutrition, Directorate of Fisheries,
Bergen, Norway)